| 摘要 |
PURPOSE:To detect accurately the traveled length of a tape independently of the use state by using a functional value F to measure a signal of the traveled length of the tape corresponding to a function H and displaying a time with this signal. CONSTITUTION:A pulse signal P1 which has a pulse duty proportional to the angular speed of a tape reel around which a tape is wound is generated, and a pulse signal P2 which has a pulse duty proportional to the angular speed of a tape reel around which the tape is wound up is generated. The sum of the square of a period T1 of the pulse signal P1 and that of a period T2 of the pulse signal P2 is measured, and the functional value F is obtained on a basis of this square sum of periods (T1<2>+T2<2>) in accordance with a functional formlula I . A ratio (x) of the number of pulses of the pulse signal P1 to that of the pulse signal P2 is measured at intervals of longer one of the period T1 of the pulse signal P1 and the period T2 of the pulse signal P2, and the signal of the traveled length of the tape corresponding to the function value H(x) obtained in accordance with a formula II is obtained. An up/down counter is used to display this signal of the traveled length of the tape as a number, for example, a 60-notation time. |
